Stab-in conduit couplings



Sept. 10, 1968 H, o, QUEBE ET AL STAB-IN CONDUIT COUPLINGS .filed May 26. 1966 2 Sheets-Sheet 1 Sept. 10, 1968 H, O, QUEBE ET AL 3,400,950

STB*IN CONDUIT COUPLINGS Filed May 26. 1966 2 Sheets-Sheet 2 I N VEN TORS United States Patent O 3,400,950 STAB-IN CONDUIT COUPLINGS Herbert 0. Quebe and Robert L. Crain, Houston, Tex.,

assignors to Gray Tool Company, Houston, Tex., a corporation of Texas Filed May 26, 1966, Ser. No. 553,245 Claims. (Cl. 285--18) ABSTRACT OF THE DISCLOSURE A stab-in tie-back sub for reestablishing communication with the cylindrical bore of a sub-sea well conduit comprising a tubular fluid confining element; means defining at least one circumferential groove in the exterior of said element and opening radially outwardly thereof, a unitary circumferentially extending slip received in said groove and protruding radially outwardly therefrom; means defining a circumferential inclined plane on said slip facing radially outwardly and slightly downwardly and having an upper edge portion arranged to frictionally engage and slide along the sub-sea well conduit bore when the sub is lowered into the bore, means defining a circumferential upwardly and outwardly facing surface on said slip intersecting said inclined plane atsaid upper edge portion and defining a sharp circumferential ridge on said slip at the intersection; and camming means between said groove and said slip responsive to incipient withdrawal of said sub from said sub-sea well conduit for moving said ridge angularly clockwise and radially outwardly into gouging engagement with said sub-sea well conduit.

The present invention relates to stab-in conduit couplings particularly useful for tying back into sub-sea, temporarily abandoned petroleum wells.

Background of the invention In the commonly assigned, co-pending US. patent application of Pitts et al., Ser. No. 539,242, filed Feb. 18, 1966, a development relating to hanging casing in sub-sea wells near the mud line so that particular wells can be temporarily abandoned upon substantial completion, during the time that nearby formation definition wells are being drilled to determine if there is a sufficient amount of recoverable petroleum in the area to warrant installation of production, collection, temporary storage and/or other similar equipment necessary to produce from the wells. One important feature of the development disclosed therein is means for separating all of the conduit risers from their respective casing strings just above the ncar-the-mud-line hangers so that a temporary abandonment cap can be placed on the well so near the mudline that the temporarily abandoned well is not a hazard to navigation.

The exemplary means shown in that application cornprise coarse cooperative threading, for instance, two pitch acme threads ladjacent the ends of the parts to be separated.-

Although the development just described has proved to be very successful in facilitating completion, temporary abandonment and tying-back into temporarily abandoned wells, the present invention grew out of anticipation that between separation of risers from mudline suspended casing strings to effect temporary abandornment and tying back into such wells, the threading on the upper ends of the sub-sea parts could become so damaged that a threaded reconnection could not be made.

Summary of the invention Accordingly, a major object of the present invention is the provision of means for tyingback into remote conduits such as mud-line suspended casing strings, sub-sea casing hanger housings and the like, which do not require relative rotation between the parts to be connected in order to form a sealed connection, even if previously used threading has become severely damaged.

A further object of the present invention is the provision of apparatus of the type described which is susceptible of reseparation by relative rotation of the connected parts.

Recognizing that the invention has broader applicability than to solution of the specific problem just outlined, it is an object of the present invention to provide an improved stab-in joint for conduits or other parts such as pressure vessel-pressure vessel closure arrangements, rodto socket couplings and the like.

These and further objects of the present invention as well as the principles and scope of applicability of the i-nvention will become more clearly apparent during the following detailed discussion relating to the exemplary embodiments depicted in the attached drawings.

Brief description of the drawings In the drawings:

FIGURE l is a fragmentary side elevation view of two conduits coupled to one another at a stab-in joint according to the present invention, one quadrant of the conduits being broken away to expose details of the joint that would otherwise be hidden;

FIGURES 2-5 comprise expanded scale, detail views of the substantially area phantom-line circled in FIGURE 1 showing various successive stages in making-up the joint shown completed in FIGURE l;

FIGURE 6 is a fragmentary elevation View of the upper mid-region of a modification of the apparatus of FIGURE 1, the slips comprising a continuous spiral, a key being provided to prevent angular translation of the slips along the tie-back sub; in FIGURE -6 parts are cut away to expose details of the key; and

FIGURE 7 is a transverse cross-sectional View substantially along line 7-7 of FIGURE 6.

Description of the preferred embodiments The sub-sea well 10 of FIGURE 1 includes an outer casing 12 driven to refusal in the sub-sea earth. The casing 12 has a casing hanger support seat 14 formed in its bore 16 about 20 feet below the mud line 18. An inner casing string 20 is shown suspended via a hanger 22 from the seat 14 and the inter-casing annulus 24 cemented up to 26. It should be noticed that both the hanger 22 and outer casing 12 terminate about five feet below the mud line 18 and for the purpose of better understanding of the invention, the well 10 should be assumed to have been temporarily abandoned after the casings 12 and 20 were emplaced and cemented, by detaching :all risers and installing a temporary abandonment cap as disclosed in the above-mentioned Pitts et al. application and that at the point shown in FIGURE l, the temporary abandonment cap has been removed, and operations begun to tie back, i.e. to reconnect conduits to the sub-sca well structure in order to allow further drilling and/or completion of the well to recommence. Specifically, the outer casing 12, which terminates in a wedge-like flange 28 has been connected to a riser 30 having a similar wedge-like flange 32 at its lower end by a remotely operable eXpansible-contractile clamp 34, sealing being provided between these parts by a fianged, two deflectable lip sealing ring 36 secured to the lower end of the riser 30. The ring 36 is of the type shown in commonly assigned U.S. Patents 2,766,- 829; 2,766,998 and 2,766,999. The riser 30 extends up to the surface Where drilling and completion operations are conducted from a platform, vessel or the like, the riser 30 serving to isolate the sea from the well, provide a conduit for lowering and raising of parts, for confining fluids and for mounting of well control equipment such as blowout preventor stacks at the surface,

It should be noticed that the hanger 22 has an axially upward annular extension 38 xed to it by threading 39 circumferential welding at 40. The bore 42 of the extension enlarges upwardly at 44 to define a frusto-conical sealing surface is cylindrically curved at 46, then threaded at 48 with, for instance, two pitch acme threads is cylindrically curved again at 50 between the threads 48 and adjacent the hanger 22 extension tlat upper end 52 which defines a stop shoulder. Closely adjacent and leading to the end 52 the bore 42 flares frusto-conically to define a guide surface 54. A plurality of angularly spaced circulation ports 56 used following the cementing operation to circulate out excess cement from the region 58 to the surface, are formed through the hanger extension 38 axially intermediate the surface 46.

In the usual course of events, personnel tying back into the well could expect to be able to lower a riser 60 with an exteriorly threaded, tapered nosed sub (not shown) at its lower end through the riser and into the bore 42 for threaded engagement with the threads 48 so that further drilling or other operations can be recommenced through and below the inner casing string 20. For the sake of further explanation of the present invention let it be assumed that such tie back procedure has been attempted, but due to damaging at 62 of the hanger extension threads 48, such a connection cannot be satisfactorily made. The riser and threaded sub are then withdrawn to the surface and a novel stab-in tie-back sub 64 according to the present invention installed on the lower end of the riser 60, for instance by complementary threading at 66 and circumferential welding at 68.

The tie-back sub 64 is generally tubular having a longitudinal throughbore 70. From its lower end or nose 72, the sub 64 exterior is first upwardly enlarging frustoconically curved at 74 complementarily to, or slightly less steeply than, the hanger extension surface 44. One or more (two shown) circumferential recesses 76 in the surface 74 receive hard hydraulic packing 78 which in its free state protrudes radially outwardly slightly beyond the surface 74. Above the surface 74, the sub 64 exterior is cylindrically curved at 80, having a radius slightly smaller than that of the surface 46 and extending axially to above the threading 48 when the parts are positioned as shown in FIGURE 1. Then the sub 64 exterior frusto-conically enlarges at 82 and is circumferentially curved at 84. The portion 84 has a radius slightly smaller than that of the surface 50 and is interrupted at several points (three shown) by circumferential radially outwardly opening annular axially spaced grooves 86. At the upper extent of the surface 84, the sub 64 exterior radially enlarges forming an annular, downwardly facing, positive stop shoulder 88 which functions to positively limit the extent of stabbed insertion of the sub 64 into the hanger extension internal bore 44. The stop shoulder 88 is positioned, relative to the frusto-conical surface 74 to engage the hanger stop 52 when the sealing material 78 has been compressed to ushness by coextensive engagement of the surfaces 44 and 74 and thus prevent over-compression of the sub lower end seal.

As best seen in FIGURE 1, the exterior of the stabin tie-back sub 64 is smooth radially adjacent the damaged threading 48 and radially smaller so that the threading 48 is not used in effecting securement of the sub 64 to the hanger extension 38. Instead, slip rings 90 received in the grooves 86 provide the required securement as will now be more fully explained, having reference to FIGURES 1-5.

Each groove 86 is shown delimited at its upper extent by a radially directed surface 92 and at its lower extent by a radially directed surface 94 of approximately half the radial extent of the surface `92. A generally cylindrically curved surface 96 extends from the apex 98 at the radially inner extent of the surface 92 about one-third the distance toward the surface 94 and a generally frusto-conical surface 100 extends from the apex 102 at the lower extent of the surface 96 to an apex 104 at the radially inner extent of the surface 94. The surface 100 is canted at an angle a of about 20 degrees.

With refe-rence to FIGURE 2, each ring 90 is shown having a radially inner, frusto-conically curved surface 106 canted about minus 15 degrees (angle with respect to the longitudinal axis of the sub 64. At its upper extent, the surface 106 is intersected at approximately a right angle by the ring upper surface 108 defining a ridge or apex 110. The surface 108 proceeds radially inwardly and upwardly at about a l0 degree angle 'y, rounding or leveling off at 112 adjacent and leading to, its radially inner upper extent. At its lower extent, the surface 106 is intersected at approximately a degree angle `by a radially short lower surface 114. The ring lower surface 114 is about one-half to one-third as wide as the groove l-ower surface 94, but `the ring upper surface 108 is about 20 percent -greater in width than the groove upper surface 92,

A first radially inwardly facing ring surface 116 extends between the point 112 and an apex at 118 intermediate the upper and lower extent of the ring where it joins a second inwardly facing surface 120 that proceeds to a juncture with the radially inner extent of the ring lower surface 114. As positioned in FIGURE 2, the surface 116 is generally cylindrically curved and of approximately the same axial length as or slightly shorter than the groove surface 96 and the surface 120 is canted at about 25 degrees (angle with respect to the longitudinal axis of the su'b 64. It should also be noticed with respect to the FIGURE 2 condition, that the total vertical height of the ring is about 20 percent shorter than the vertical distance between the groove upper and lower surfaces 92, 94 and that in the at rest position of FIGURE 2, the ring 90 rides intermediate the upper and lower surfaces of the groove with roorn for movement upwardly as well as downwardly from the position shown.

The rings 90 can each be radially split at a stage in their manufacture so as to be readily radially expansible sufficiently to lbe snapped into the respective grooves 86 as the sub 64 is being made up. When snapped in place, the ends of the rings should engage or nearly engage when in condition thereof so that the rings will function properly throughout the sequence illustrated in FIGURES 3-5.

A sub 64, made up as just described and with rings 90 positioned as shown in FIGURE 2 is lowered via the riser or pipe 60 into the riser 30 and downwardly through the casing 12 bore 16. The tapered nose '72 is yguided into the yhanger extension bore 42 by the flared end region 54 of the bore.

As lowering continues, the ring apices causing the rings to move slightly inwardly and upwardly as shown in FIGURE 3 until the points 112 engage the respective upper surfaces .of the grooves 86. At this point, the ring apices 118 are nestled in the respective groove apices 102 and the ring surfaces 116 coextensively engage the respective groove surfaces 96, In this downward movement the ridges 110 do not plow into the han-ger extension bore surface 50 because of the comparative lowness of the angle but rather are shoe-horned along this surface. Engagement at 52, 88 terminates downward movement of the sub 64 and prevents over-running of the seal formed at 44, 74. The weight of the pipe 30 is sufiicient to bring the sub to the stabbed-in stopped yand locked condition shown in FIGURE l. Any tendency of the sub 64 to move upwardly from the FIGURE 1 position causes the rings 90 to angularly rotate (arrow e) about the apices 118, as progressively shown in FIGURES 4 and 5, forcing the sharp edges 110 to bite into the wall of the hanger body 38 (FIGURE 4) and moving the surfaces 100 and 120 into engagement. Further upward movement of the sub `64 (FIGURE 5) causes the rings 90 to be cammed radially outwardly as the surfaces 100v slide along the respective surfaces 120 thereby forming substantial bites or tapered annular sockets 122. Relative movement is positively stopped when the ring sur-faces 114 engage the groove surfaces 94. The entire upward movement of the sub 64 between FIGURE 3 `and FIGURE 5 in the illustrated example is only about three thirty-seconds of an inch and is insuliicient to break the seal at 44, 7S.

It should now 'be apparent that the hanger `body 22, 38 has been tied back into efiiciently irrespective of rthe damaged threading at 62 and that yfurther completion of the well 10 can now be undertaken, The slips 90 are considered advantageous because they operate -within conventional interelement radial spacing, are self-energizing and not susceptible to easy failure, are quick acting and require a minimum of vertical relative movement to set, are easy to manufacture and assemble, and have broad applicability.

It should be appreciated that the sli-ps `SP must be made of sufiiciently tough material that they will gouge the :wall of the hanger body extension rather than .being plastically deformed themselves. Aside from this consideration, many materials can be used to fabricate the slips 90 and accordingly the following examples of properties should be considered in a non-limitative sense.

A modified stab-in tie back sub 64' is illustrated in FIGURES 6 and 7 received in the bore of a hanger body 38 as in FIGURE 1. The sub 64 differs from the sub 64 by having a single multiple turn, spiral groove 86 rather than a plurality of individual, annular grooves; in having a single spiralled slip 90' received in the groove 86' and in having a key 130 mounted so as to prevent translation of the slip 90 along the groove 86'. In other respects, the two subs are structurally alike and the slip 90 functions during tie back operations as described in relation to FIGURES 2-5. Accordingly, corresponding parts have been given primed numerals. After the slip 90 has been disposed in the groove 86' means are provided to prevent relative angular rotation between the slip and the groove. In the embodiment illustrated, the sub exterior and slip have been grooved at 132 with a longitudinally elongated, arcuately narrow, radially outwardly opening channel that is cut approximately halfway through the slip 90' a key in the form of a strap 130 is received in the channel 132 overlying the slip 90' and welded to the sub 64' at 134, its opposite end regions. As 'best seen in FIGURE 7, the strap 130 is insufficiently thick to engage the hanger body bore, there being a gap 136 between the radially outer surface of the strap and the bore. The structure shown is preferred because it results in positive locking of each turn of the spiralled slip 90', however, it is intended to be exemplary in the sense that other slip locking means could be ernployed, such as depositing weld material in the channel 86' immediately adjacent the two ends of the slip 90'.

Referring to FIGURES 4, 5 and 6, it should be apparent that the slip 90 corner 110 cuts a spiralled gouge or groove in the hanger body Wall, rather than annular grooves 122 as it is non-rotatively stabbed into place. Accordingly, if the need should arise to disengage the sub 64 from the casing hanger body 38, this can be easily achieved by rotating the sub 64 with respect to the casing hanger body, whereupon the slip 90 corner 110' spirals along the groove it has cut in the hanger body wall and the parts are as simply threadably disengaged as if they had been conventionally prethreaded parts. The fabrication materials for the FIGURE 6 and 7 embodiment can be the same as those described above in relation to the embodiment of FIGURES 1-5.

It should now be apparent that the embodiments described hereinabove clearly illustrate the` principles of the present invention and that the invention'achieves each of the objects set forth at the outset of this specification. Because the specific embodiments can be considerably modified without departing from these principles or failing to accomplish these objects, the present invention should be understood as encompassing all such modifications as are within the spirit and scope of the following claims.

We claim:

1. In combination: a first part having means defining a generally cylindrical bore therein communicating with the exterior of the first part at means defining a mouth; a second part constructed and arranged to be stabbed into said bore through said mouth; and securement means received between said first and second parts for preventing non-rotative withdrawal of the second part from the bore of the first part; the securement means comprising: means defining at least one circumferential groove in one part opening toward the 'other part of said first and second parts; a unitary circumferentially extending slip received in said groove and protruding therefrom toward said other part; said slip extending about at least one half the circumference of said one part; means defining a circumferential inclined plane on said slip facing away from said mouth and constructed and arranged to frictionally engage said other part and ease.` advancement of the second part in the first part bore; means defining a sharp circumferential ridge on said slip at the trailing edge of said circumferential inclined plane; and camming means between said groove and said slip responsive to incipient withdrawal of said second part from the bore of said first part for moving said ridge into gouging engagement with said other part; said ridge being composed of harder material than said other part; said groove being axially wider than said slip and the camming means comprising means defining a first canted circumferential surface on said one part within said groove, said rst canted surface facing both said other part and said mouth and a second canted surface on said slip facing both away from said other part and away from said mouth; said second canted surface being engageable with `and slidable along said first canted surface; said second canted surface being canted slightly more than said first canted surface with respect to the longitudinal axis of said bore; and further including means defining a first generally cylindrically curved surface on said one part within said groove extending generally parallel to said longitudinal axis from a first line intersection with said first canted surface toward said mouth, said first line intersection delining a first circumferential apex, and means defining a second generally cylindrically curved surface on said slip extending generally parallel to said longitudinal axis from a second line intersection with said second canted surface toward said mouth, said second line intersection defining a second circumferential apex; said first and second generally cylindrically curved surfaces being of approximately equal axial length; said slip having a rest position intermediate the upper and lower extent of said groove wherein the second circumferential apex circumferentially engages said frst canted surfaces intermediate the axial extent thereof, said slip being translatable axially in said groove between the upper and lower extent thereof and rockable about said second circumferential apex, between a first condition wherein the slip is relatively retracted and said first and second generally cylindrically curved surfaces are in coextensive engagement and a second condition wherein the slip is relatively extended and said first and second canted surfaces are in surface to surface engagement.

2. The combination of claim 1 wherein in said rest position the axial extent of said slip approximates percent of the axial extent of said groove, the angular disparity between said first and second canted surfaces is approximately 2 degrees, said slip circumferential inclined plane makes an approximately 15 degree angle with the longitudinal axis of said bore and said sharp circumferential ridge is defined by the juncture of means defining the upper surface of said slip and the trailing edge of said circumferential inclined plane, said upper surface also intersecting the second cylindrically curved surface at the upper extent thereof and defining an uppermost limit stop on said slip.

3. The combination of claim 1 wherein said slip comprises an annular ring and wherein said groove is annular.

4. The combination of claim 1 wherein said slip comprises a spiral having a plurality of turns and said groove comprises a spiral having a plurality of turns, said second part being thereby constructed and arranged to be rotatably withdrawable from said bore of the first part.

5. The combination of claim 4 further including means defining a generally axially directed channel in said one part opening toward said other part, said channel intersecting and incompletely broaching said slip spiral turns; and a strap received in said channel, said strap being sesured to said one part overlying said slip spiral turns; said strap being insufficiently thick to protrude as far as said slip toward said other part.

6. The combination of claim 1 wherein said one part is said second part and wherein said other part is said first part.

7. The combination of claim 6, the first part comprises a sub-sea mounted first tubular fluid confining element and wherein said second part comprises a second tubular iiuid confining element lowerable from the sea surface for tying back into said first tubular fluid confining element.

8. The combination of claim 7 further including circumferential sealing means defined on the sub sea fluid conning element within said bore and circumferential sealing means defined on the second fluid confining element positioned for sealing engagement with the firstmentioned sealing means; and a stop shoulder formed on said second fluid confining element for engagement with the sub sea fiuid confining element engageable to limit advancement of said second fluid confining element into said bore and to prevent overrunning of said seal.

9. The combination of claim 8 wherein the stop shoulder comprises an exterior, annular circumferential flange on said second fluid confining element arranged to engage the upper end of the sub-sea fluid confining element; and wherein the sealing means comprise complementarily tapered frusto-conical surfaces and resilient sealing material received between the last-mentioned surfaces.

10. A stab-in-tie-back sub for reestablishing communication with the cylindrical bore of a sub-sea well conduit comprising: a tubular iiuid confining element; means defining at least one circumferential groove in the exterior of said element and opening radially outwardly thereof; a unitary circumferentially extending slip received in said groove and protruding radially outwardly therefrom, said slip extending at least about halfway around said element;

means defining a circumferential inclined plane on said slip facing axially downwardly and radially outwardly at a relatively small acute angle to the longitudinal axis of said element; means defining a sharp circumferential ridge on said slip at the trailing edge of said circumferential inclined plane; and camming means between said groove and said slip responsive to incipient axial withdrawal of said tie-back sub once stabbed-in, for moving said ridge into gouging engagement with the sub-sea well conduit bore; said groove being axially wider than said slip and the camming means comprising: means defining a first canted circumferential surface on said element within said groove, said first canted surface facing radially outwardly and axially upwardly of said element, and means defining a second canted surface on said slip facing radially inwardly and axially downwardly of said element; second canted surface being engageable with and slidable along said first canted surface; said second canted surface being canted slightly more than the first canted surface with respect to the longitudinal axis of said element; and further including means defining a first generally cylindrically curved surface on said element within said groove extending generally parallel to said longitudinal axis, axially upwardly from a first line intersection with said first canted surface, said first line intersection defiining a first circumferential apex; and means defining a second generally cylindrically curved surface on said slip extending generally parallel to said longitudinal axis axially upwardly from a second line intersection with said second canted surface, said second line intersection defining a second circumferential apex; said first and second generally cylindrically curved surfaces being of approximately equal axial length; said slip having a rest position intermediate the upper and lower axial extent of said groove wherein the second circumferential apex circumferentially engages said first canted surfaces intermediate the axial extent thereof, said slip being translatable axially in said groove between the upper and lower extent thereof and rockable about said second circumferential apex, between a first condition wherein the slip is relatively retracted and said first and second generally cylindrically curved surfaces are in coextensive engagement and a second condition wherein the slip is relatively extended and said first and second canted surfaces are in surface to surface engagement.

References Cited UNITED STATES PATENTS 1,995,006 3/1935 Mueller 285-321 X 2,110,127 3/1938 Hinderliter 285-332.2 X 2,174,076 9/1939 Bowen 285-144 2,644,524 7/1953 Baker 285-141 X 3,054,628 9/1962 Hardy 285-3323 3,163,217 12/1964 Haeber 285-144 X 3,163,222 12/1964 Foster 285-18 X CARL W. TOMLIN, Primary Examiner. R. G. BERKLEY, Assistant Examiner. 

